Imaginary Industries

So I’ve been working on the HMV Freeway a bunch recently. I actually have it driving (until the CVT drive pulley, which I forgot to tighten properly left the building with a bang), but I’m backing up a bunch here to try to go over what I’ve done.

So, after the last post, I had fiberglassed-in the nose, but the exterior face was still very concave, because I didn’t have the mold working right. I ran with it, but it needed a lot of finessing.

First step was do the major filling. This is 2 lbs of bondo hair (yes, really). Basically, it’s bondo mixed with chopped fiberglass. You can also see there are two little 3d-printed mold insets to shape the screw cavities in the mess. They were treated with parting wax, and came out very easily afterwards.

This worked well, except I had once spot that didn’t cure well. I suspect this was mostly because the fiberglass in this makes it very difficult to completely mix, and I was mixing way too much at once (basically, all of it), so I didn’t have time to be super thorough before it started cooking off.

I then sanded it smooth(ish).

I then had the brilliant idea “why don’t I just cover all this crap with vinyl wrap.”

It turns out doing vinyl wraps well is freaking hard, and I think the whole nose of this might be one of the most difficult shapes to wrap properly. Most cars are mostly flat surfaces, or simple one-axis arcs. This….. is not.

And then moved onto normal bondo.

I then spent the next 2 or so weeks trying to get a good paint result that I liked. This is made harder by the fact that this has been repainted at some point (it originally Red!). At this point, I think I’ve tried every version of spray-paint orange I can find locally.

I’ve also done a few more sanding/bondo cycles. The crease carrying over the nose is still not quite where I want it to be, but I’m giving up at the moment.

I had ideas about the thing being two-tone, but that would involve shaping the color on the front a lot more carefully. I may revisit this idea.

I’ve also had a bunch of other stupid issues that make the paint even more complicated. I 3d printed some light mounts, and then installed them:

Of course, because I’m an idiot, I put the left-side one on the right, and vice versa. I also used some foam rubber double-sided tape to seal them on, and when I went to pull them off, well:

The paint just peeled off in sheets. There were large sections where there was no double-sided tape involved, it just flaked free:

Yep, whoever did the paint the previous time did a shit job, and the color coat delaminated from the primer. I’m confident that there is primer becase when I sanded through it on the nose area, it comes up bright red. The dark burgundy is between the orange paint and the red.

This isn’t the only area where the current paint-job is…. not great. On the rear section:

I installed some additional turn-signal indicators from a motorcycle, because the two tail lights on this thing are effectively indistinguishable from a distance. When doing this, I put some blue painters tape on the body, marked that with a sharpie, drilled, and when I went to remove the blue painters tape (after maybe 40 minutes), it pulled big chunks of the clear-coat off.

So, since I am relocating the fuel tank to the front of the freeway to accommodate the moved seat, that means I need to cut out and fill in the existing headlight bucket, since it protrudes a long way into the interior where the fuel tank is now located.

I spent a bunch of time trying to get a good measurement of the front-end geometry, to make a mold for the replacement fiberglass. I initially was hoping to use the 3d scanner I have (a revopoint metro-x), but it doesn’t have the greatest tracking, and the gloss paint finish really makes scanning the thing extremely difficult.

I sprayed it down with scanning spray, but that was after I had applied all the tracking markers, and the scanning spray is apparently matte enough to block the tracking marker dots.

Anyways, I eventually wound up using the non tracking dot based scan mode, and got something usable. I then 3D printed a mold block to try to glass-against.

Moving on, I flipper the body top over and got to hacking:

I then feathered the edges of the cutout down to a sharp edge by sanding them down on the interior of the shell, and trying to be clever, attempted to use a vacuum pump to conform a silicone sheet to the geometry of the 3d printed mold, and also to hold the mold in place:

While the vacuum held the mold on fine, it didn’t have enough grunt (or there was a leak I didn’t find) to pull the thin silicone sheet into the full mold geometry. Since I wanted to get this done, I just went with it. I’m going to have to add a /bunch/ of filler to properly shape the nose out in the future, but the strength is back in it, in any event.

I wound up doing 2 layers of fiberglass, and then going to get food, before removing the mold and then adding more layers.

Of course, a bird took the opportunity to poop on the new fiberglass while I was at lunch.

I eventually wound up with 8 layers of fabric feathered into the existing body.

One of the major things needed on the freeway to make it properly drivable is replacing the fuel tank, since it has a vapor leak /somewhere/.

Anyways the fuel tank was kind of a messy story. I designed a tank that was supposed to fit next to the battery behind the seat. This lead to a squat, large tank (10” dia by 12” long).

I will say I ordered the seat from Bam Industries / https://spunaluminumgastanks.com. Apparently you can just email them a custom tank design (assuming it’s made with their standard fittings), and it effectively costs no more then any of the tanks from their website with the same feature set.

This tank wound up being $359 shipped, with all the tweaks I specified.

Once the tank was ordered, and before it showed up, I lowered the seat, which lead to me moving it backwards as well to improve driving comfort. I also started considering moving the battery to the front of the vehicle, since I know at least one other person has done that. That means that the tank I had already ordered was now designed to accommodate constraints that no longer existed, and the new location of the seat meant it would be fiddly to fit and require me to adjust the seat forwards enough that it was less comfortable.

The tank arrived, and looks really nice:

My only real complaint is that the mounting rings they ship with the tank have no paint, and are plain steel, so you have to coat them somehow. Otherwise, it’s a very nice unit.

At this point, I had the body off, and my housemate asked why I didn’t move the tank up to the big open area in the front.

This entails even more changes, since the tank will fit fine up front if I cut out the integrated heatlight bucket. I also have to rework a bunch of the brake lines since the tank will now go right where they cross from the right to left hand side of the vehicle.

Anyways, a bunch of fiddling and mockup later, I used terriblwelder to put together a cross-member mounting frame to hold the tank up front. I continue to be rather surprised by how capable even the cheapest flux-core welder is.

The cross member is bolted to the existing freeway frame with rivnuts and 1/4-20 grade 8 bolts. I also used them to hold the mounting hoops to the cross-member. I’m OK with using rivnuts here since the bolts are all located in shear in the case of a collision anyways, and rivnuts have a much stronger pull-out force resistance then I initially thought (1/4-20 has ~500 lbs pull-out in thin material!).

The tank is offset to the right hand to clear the master cylinder (which mounts in the hole in the bracket on the left-hand side, right hand of the above image).

So, since I’m planning on doing a bunch of work on the freeway, I decided to pull the top half of the body off. This is very easy to do, since it’s effectively held on with 8 bolts and a few sheet metal screws (they hold the edges of the fiberglass together so they don’t rattle).

I have a old 1-ton chain fall and I rigged up a mounting eyelet in my carport to make this easier to do with one person. The top of the body is probably ~60-80 lbs, but it’s a large and awkward shape, and you have to jiggle it around to fit the rear section over the trailing frame bars.

Anyways, a bunch of ratchet straps and some mildly careful balancing and it comes off without too much work.

I also got the chance to discover how terrible the existing wiring was. Completely re-wiring the entire car is now another thing I need to plan on doing.

Amusingly enough, whoever redid this car last used MDF pegboard for the interior! I’m not planning on replacing any of the interior paneling, I’m OK with the frame being visible inside the car.

I also took the opportunity to pull the engine to give it a once-over (it’s leaking a bit somewhere), and remove the governor.

First, we can see this thing has had a pretty bad exhaust leak for a while. It turns out the upper bolt-hole for the exhaust is largely stripped. I got it together once during reassembly, but it really needs to be helicoiled.

Since this uses a literal Tecumseh utility engine, it comes with a governor to stop the engine from going more then a few thousand RPM. While this is a overhead-valve engine (with pushrods! and only splash lubrication!), I’m not sure how high I can rev it without something failing.

I’m going to find out.

Long term, I’d like to graft a proper motorcycle powertrain (I’m actually thinking the entire back half of a motorcycle) onto the rear of the thing. I need to re-engineer the front suspension before that, though.

So first order to actually fit myself in the freeway is moving the seat down and back.

Seat Relocation

So the freeway, as stock (I believe) had a funky seat mounting system, where the seat front is effectively mounted on a horizontal dowel, and the rear just sits on some adjustable feet. This then sits on top of a funky tube-steel structure, which I believe was designed to clear the extended fuel tank option (the 9 gallon fuel tank option mounted under the seat).

I cut the seat mounting angle-structures off with a grinder, and rebuilt the mounting structure out of 1” x 1/4” flat bar.

This was all done with the worst welder possible. A few years ago, I bought literally the cheapest wire-feed welder I could find on amazon, mostly out of curiosity (I think it was ~$70). It only does flux-core welding. It’s…… surprisingly not /that/ bad?

Anyways, I fixtured the new seat mount by putting it ontop of the old mount, and put bolts through them to keep things aligned. This didn’t work as well as I had hoped, since the holes in the old mount are way oversized, and since the new mount has appropriately sized holes, one side does not line up (gah).

Fortunately, I’ve been planning on improving the seat mounting anyways (switching to grade 8 bolts), so I should be able to fix that issue pretty easily.